Engine-CodesScion – P0504 Scion

P0504 Scion Code - Brake Switch Circuit 'A' / 'B' Correlation

Quick Answer

The P0504 code for Scion vehicles refers to a problem with the Brake Switch Circuit 'A' / 'B' correlation. Common causes include Faulty brake light switch, Damaged wiring or connectors in the brake light circuit, Malfunctioning ECU. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0504 Scion indicates Brake Switch Circuit 'A' / 'B' Correlation.
Common causes
Common causes include Faulty brake light switch, Damaged wiring or connectors in the brake light circuit, Malfunctioning ECU.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Table of contents Created and updated by William Orellana on Sep 10, 2024
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Code P0504 Scion Description

The P0504 code for Scion vehicles refers to a problem with the Brake Switch Circuit 'A' / 'B' correlation. This code indicates that there is a discrepancy between the signals being sent by the brake light switch circuit 'A' and 'B'. The brake light switch is a crucial component in a vehicle's braking system, as it signals to the vehicle's electronic control unit (ECU) when the driver is applying the brakes. When there is a correlation issue between the two circuits, it can impact the vehicle's performance and safety.

OBDII Code P0504 Scion - Brake Switch Circuit 'A' / 'B' Correlation
P0504 Scion Code - Brake Switch Circuit 'A' / 'B' Correlation

Common Causes of P0504 Scion

  1. Faulty brake light switch
  2. Damaged wiring or connectors in the brake light circuit
  3. Malfunctioning ECU
  4. Corrosion in the brake light switch circuit
  5. Loose or disconnected brake light switch

Symptoms of P0504 Scion

  1. Erratic operation of the brake lights
  2. Inability to shift out of park
  3. Cruise control not functioning
  4. Traction control issues
  5. Vehicle going into limp mode

How to Fix P0504 Scion

  1. Begin by diagnosing the issue using a scan tool to confirm the P0504 code.
  2. Inspect the brake light switch for any signs of damage or wear and replace if necessary.
  3. Check the wiring and connectors in the brake light circuit for any damage, corrosion, or loose connections.
  4. Test the ECU to ensure it is functioning correctly and replace if needed.
  5. Clear the diagnostic trouble codes, test drive the vehicle, and recheck for any recurring issues.

Cost to Fix P0504 Scion

The cost of resolving a P0504 code on a Scion can vary depending on the specific cause of the issue and the labor rates in your area. On average, the repair cost could range from $100 to $300, including parts and labor. It's important to keep in mind that prices can fluctuate based on the location of the repair shop, the make and model of the vehicle, and the extent of the repairs needed. It's recommended to consult with a trusted mechanic or repair shop to get an accurate estimate for your particular situation.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0504 Scion Code

No Frequently Asked Questions about P0504 Scion Code found.

Discuss the causes and fixes for P0504 Scion OBDII Code

  • I have a 2009 Scion XD.

  • I noticed for the past several months that when I stepped on the brakes with the A/C turned on it would loose power or my mph gage would drop lower than normal (idle). Could my Brake Light Switch some how be the cause of this issue? I had a friend use his machine to diagnose any issues and the only thing that he could get off of his machine was the P0504 code for my Brake Light Switch Circuit 'A'/'B' Correlation.

    When the car is on and the A/C is not running everything operates perfectly fine no issues or problems with anything. As soon as I turn on the A/C is when everything from constant vibrations and a lower idle start to take place. Does any one out there own a scion XD and have had similar problems with the vehicle? I would greatly appreciate some help or feedback about this issue I'm having.

    I did not take it in to the dealer ship yet. I was hoping to get some answers first to better understand the problem.